Tiger Woods announced Wednesday he is withdrawing from next week's AT&T National, the tournament he hosts at Aronimink Golf Club in Newtown Square, Pa. Woods was initially diagnosed with a "mild" Grade I MCL sprain when he hurt himself hitting out of an awkward stance at the Masters, but Dr. Ronald Grelsamer, an orthopedic surgeon at The Mount Sinai Hospital, is a bit skeptical. "My initial thought was it had to be more than a Grade I knee sprain. You just don't get that playing golf and if you do, you recover pretty quickly," he said. Learn More.